LOWER GASTROINTESTINAL BLEEDING LGIB BY Ahmed Mohammed Hassan

LOWER GASTROINTESTINAL BLEEDING (LGIB) BY Ahmed Mohammed Hassan Abo El. Magd Assistant lecturer at GIT surgery department

DEFINITION Acute LGIB has been defined as bleeding that is of recent duration, originates beyond the ligament of Treitz, results in instability of vital signs, and is associated with signs of anemia with or without the need for blood transfusion.

Problem magnitude Lower gastrointestinal bleeding (LGIB) accounts for approximately 20%-33% of episodes of gastrointestinal (GI) hemorrhage. However, although LGIB is statistically less common than upper GI bleeding , it has been suggested that LGIB is underreported because a higher percentage of affected patients do not seek medical attention. LGIB continues to be a frequent cause of hospital admission and is a factor in hospital morbidity and mortality, particularly among elderly patients.

Causes of lower gastrointestinal bleeding (LGIB) Diverticular bleeding A diverticulum is a saclike protrusion of the colonic wall most commonly located in the sigmoid and descending colon. Bleeding is usually acute, without antecedent symptoms, and it is self-limited in about 70%-80% of cases. Although diverticular bleeding is painless, patients may experience mild abdominal cramping due to the intraluminal blood that triggers spasmodic contractions of the colonic wall. Rebleeding can occur in up to 25% of patients. If the bleeding is brisk and voluminous, patients may be hypotensive and display signs of shock.

Angiodysplasia Colonic angiodysplasias are arteriovenous malformations (AVMs) located in the cecum and ascending colon; these are acquired lesions that affect elderly persons older than 60 years. Most colonic angiodysplasias are degenerative lesions that arise from chronic, intermittent, low-grade colonic contraction that obstructs the mucosal venous drainage. Over time, mucosal capillaries dilate, become incompetent, and form an AVM.

Significant angiodysplasia-related bleeding, like diverticular bleeding, presents as painless, selflimited hematochezia or melena; angiodysplasiarelated bleeding is venocapillary. Unlike diverticular bleeding, angiodysplasia tends to cause slow but repeated bleeding episodes. Therefore, patients may present iron-deficiency anemia, and syncope. Occasionally, patients can present with large-volume bleeding.

Colitis Ischemic colitis May or may not present with abdominal pain and associated bloody diarrhea. The bloody diarrhea is self-limited but can recur if the underlying cause is not corrected. Patients with ischemic colitis are usually older and have cardiovascular comorbidities. Ischemic colitis may be fulminant, presenting with acute abdominal pain, rectal bleeding, and hypotension, or this condition may be insidious.

Inflammatory bowel disease Massive hemorrhage due to inflammatory bowel disease (IBD) is rare. Ulcerative colitis causes bloody diarrhea in most cases. In up to 50% of patients with ulcerative colitis, mild to moderate LGIB occurs, and approximately 4% of patients with ulcerative colitis have massive hemorrhage. LGIB in patients with Crohn disease is not as common as in patients with ulcerative colitis; 1%-2% of patients with Crohn disease may experience massive bleeding. The frequency of bleeding in patients with Crohn disease is significantly more common with colonic involvement than with small bowel involvement alone

Colon carcinoma The bleeding associated with colon cancer, particularly right-sided bleeding, can be insidious, with patients presenting with irondeficiency anemia and syncope. Right-sided colon cancer may also present with maroon stools or melena, whereas left-sided colonic neoplasms can present as bright red blood per rectum, which can sometimes be confused with hemorrhoid bleeding.

Anorectal disease Hemorrhoidal bleeding is most often painless, whereas bleeding secondary to fissures tends to be painful. Hemorrhoids can also present with strangulation, hematochezia, and pruritus. Typically, bright red blood coats the stool at the end of defecation or blood may stain the toilet paper. Rarely, the bleeding may be copious and distressing to the patient.

Drug-induced bleeding is caused mainly by NSAID and aspirin use, and it is more common in the elderly. Although the risk of bleeding increases at higher doses of these agents, even low-dose aspirin given for cardiovascular prophylaxis can produce bleeding. Using the lowest effective dose for both short and long-term users is recommended. Aspirin or anticoagulants can potentiate or aggravate hemorrhage from preexisting lesions.

Evaluation of bleeding The initial evaluation of a patient with a suspected clinically significant acute lower GI bleed includes a history, physical examination, laboratory tests, and in some cases, nasogastric lavage. The goal is to assess the severity of the bleed, identify potential sources of the bleed, and determine if there are conditions present that may affect subsequent management.

Signs and symptoms Ø Ø The clinical presentation of LGIB varies with the anatomical source of the bleeding, as follows: Maroon stools, with LGIB from the right side of the colon. Bright red blood per rectum with LGIB from the left side of the colon. Melena with cecal bleeding. LGIB can be mild and intermittent, as often is the case of angiodysplasia and colon carcinoma, or moderate or severe, as may be the situation in diverticula-related bleeding. Colon carcinoma rarely causes significant LGIB

Specific causes of LGIB may be suggested by the patient's symptoms Ø Ø A young patient may present with fever, dehydration, abdominal cramps, and hematochezia caused by infectious or noninfectious (idiopathic) colitis. An older patient may present with painless bleeding and minimal symptoms caused by diverticular bleeding or angiodysplasia. LGIB can be mild and intermittent, as often is the case with angiodysplasia, or it may be moderate or severe, as may be the situation in diverticula-related bleeding. Young patients may present with abdominal pain, rectal bleeding, diarrhea, and mucous discharge that may be associated with IBD.

Ø Ø Elderly patients presenting with abdominal pain, rectal bleeding, and diarrhea may have ischemic colitis, or elderly patients with atherosclerotic heart disease may present with intermittent LGIB and syncope that may be due to angiodysplastic lesions. Stools streaked with blood, perianal pain, and blood drops on the toilet paper or in the toilet bowl may be associated with perianal pathology, such as anal fissure or hemorrhoidal bleeding.

Ø The physical examination should be thorough and include the skin, oropharynx, nasopharynx, abdomen, perineum, and anorectum. Therefore, nasogastric tube insertion, digital rectal examination, and anoscopy/proctoscopy should be part of the initial physical examination in all patients.

Laboratory data § § § Complete blood cell (CBC) count. Serum electrolyte levels. Coagulation profile, including activated partial thromboplastin time (aptt), prothrombin time (pt), manual platelet count, and bleeding time.

Helical CT scanning Helical CT scanning as a diagnostic tool for acute lower GI bleeding (LGIB) is a safe, convenient, and an accurate diagnostic tool relative to mesenteric angiography and colonoscopy. Helical CT scanning of the abdomen and pelvis can be used when a routine workup fails to determine the cause of active gastrointestinal (GI) bleeding. Multiple criteria, including vascular extravasation of the contrast medium, contrast enhancement of the bowel wall, thickening of the bowel wall are used to establish the bleeding site with helical CT scans.

Colonoscopy Ø Ø Ø In most patients with lower gastrointestinal bleeding (LGIB), colonoscopy is the initial diagnostic method of choice. Colonoscopy is successfully used to identify the site of severe LGIB in approximately 74%-82% of patients. In addition to its diagnostic utility, colonoscopy offers the opportunity for therapeutic intervention. Actively bleeding lesions can be treated with colonoscopic thermoregulation, epinephrine injection, photocoagulation, clip application, and a combination of these methods.

Candidate for urgent colonoscopy Ø Ø Candidates for urgent colonoscopy should be properly screened and include patients who are hemodynamically stable with no ongoing brisk bleeding, because the diagnostic yield is otherwise lowered in such patient populations. Thus, the best candidates for urgent colonoscopic evaluation are patients who are bleeding slowly or who have already stopped bleeding. The bowel should be well prepared, with a rapid oral purge (or via NG tube in selected patients), because performing an urgent colonoscopy on an unprepared bowel is difficult and frequently unsuccessful.

Disadvantages of colonoscopy 1. 2. 3. 4. Urgent or emergent colonoscopy must be performed by skilled endoscopists. Urgent colonoscopy requires a bowel preparation that can cause a 4– to 6–hour delay. Perforation during the examination is possible, particularly in a patient who is ill. Colonoscopy carries the risks of sedation for patients who are acutely bleeding.

Angiography Consider emergency angiography as an initial study for hemodynamically unstable patients with ongoing bleeding who are not likely to tolerate bowel preparation and colonoscopy. Once the bleeding point is identified, angiography offers potential treatment options, such as selective vasopressin drip and embolization The advantages of angiography include: (1) This modality provides accurate localization of the bleeding; (2) it has a therapeutic utility that includes the use of vasopressin infusion or embolization; and (3) it does not require preparation of the bowel. The disadvantages of angiography include: (1) It has a sensitivity of approximately 30%-47%; (2) it can only be performed during active bleeding; and (3) it has a complication rate of about 9%. Such complications include thrombosis, embolization, and renal failure

Management of LGIB Ø The emergency implementation of aggressive resuscitation, diagnostic evaluation, and early involvement of a gastroenterologist (and surgeon in the case of a rapid LGIB) is key to reducing morbidity and mortality and to improving outcomes.

Massive LGIB is defined when: Ø Ø Ø Passage of a large volume of red or maroon blood through the rectum. Hemodynamic instability and shock. Initial decrease in hematocrit (Hct) level of 6 g/d. L or less. Transfusion of at least 4 U of packed red blood cells (PRBCs). Bleeding that continues for 3 days. Significant rebleeding in 1 week.

Resuscitation and Initial Assessment Ø Ø Initial resuscitation involves establishing largebore IV access and administration of normal saline. Blood should be typed and cross-matched. PRBC transfusions should maintain the hemoglobin level above 7 g/d. L, with a threshold of 9 g/d. L in those with massive bleeding or significant comorbid conditions, or if there may be a delay in more definitive treatment.

Insert an NG tube to confirm the presence or absence of blood in the stomach. Place a Foley catheter to monitor urine output. Careful digital rectal examination, anoscopy, and rigid proctosigmoidoscopy should exclude an anorectal source of bleeding.

Initial Approach to Hemostasis In patients who are hemodynamically stable with mild to moderate bleeding or in patients who have had a massive bleed that has stabilized, colonoscopy should be performed initially. Once the bleeding site is localized, therapeutic options include coagulation and injection with vasoconstrictors or sclerosing agents.

Surgical indications 1. 2. 3. Persistent hemodynamic instability with active bleeding. Persistent, recurrent bleeding. Transfusion of more than 4 units packed red bloods cells in a 24 -hour period, with active or recurrent bleeding.

Ø Ø Ø Segmental bowel resection following precise localization of the bleeding point is the preferred treatment because of its low postoperative morbidity and mortality when compared with subtotal colectomy. Subtotal (total abdominal) colectomy with temporary end ileostomy is the procedure of choice in patients who are actively bleeding from an unknown source. Blind segmental resection should not be performed because of a prohibitively high